Treating coal gases



March 8 1932. F. BONN'E'MANN 1,348,156

TREATING COAL GASES Filed Nov. '29, 1929 WASHER El :6 e146 FREED FROM H 5 AMMONIA WASHER creuoz ans BRRN LHED OFF Gag CQNDENsRT'E CONTFHNING NHg HMMONIA LIQUOR 4 23 HMMONIH vAPoRs 75 RESERVOIR CONDENSHTE 59/12 50 m ma/m Patented Mar. 8, 1932 T NT FRAnz-BouNn ANN, or ESSEN-RUHR, enaivmum nssmuoa, IBY nnsnn ASSI NMENTS; TO THE KOPPEZR-S COMPANY, or PITTSBURGH, PENNSYLVANIA, A CORPORATIONQF gases. It has particular reference to thepur- DELAWARE TREATING- COAL GASES Application filed November 29, 1929-, Serial No. 410,586, and in Germany February 4, 1928.

FMyinve'ntion, for which application for gases with a. view toseparating and recover ing therefrom the ammon1a,hydrogen sulfide and other val'uablematter contained in these ification of coal and coke oven-gases and to the recoverytherefrom of the valuable by products contained therein,- a 7. I In "the processes hitherto known for re-.

' covering hydrogen sulfide contained infcoal distillation gases such'as for instance coke oven gases means have been 'provided for combining. the hydrogen sulfidewiththe ammonia contained in the gas which isthus freed from sulfur. The processes operating on this rinciplehave proved toibe satisfac tory as ong as the ratio of the ammonia to v hand, ifa'mmonia and hydrogen sulfide are the-hydrogensulfide is 2:1. On the other present in-the gas in [a different ratio, for instance if hydrogen sulfide is. present n excess, these processes will either fail or it wilhbe extremely difficult to carry. them through. In this case a1lthatcan be done oflthis ammonia, so that only this quantity is to add to the gas'hnder treatment a quantity" of ammonia which restores the ratiofof 2 ammonia to 1 hydrogen sulfide. Obvlously this quantity of ammonia not being available as a rule must be bought and paid for.

It is an object of 'myinvention to. separate" from the "gases" all the ammonia" contained therein, at the same time causingone part hydrogen'sulfide to combine with two parts of hydrogen sulfide is recovered. order to Reflect this, aquantityfof 'gas correspond ing to the surplus of hydrogen sulfide' "con tained in the gas beyondthe proportion of 2 v ammonia to 1 hydrogen-sulfide'is'branched Ofihbeforeffi'ecting the combination ofthe while the gas in the bran'ch current which has 5 thusibeen freed from its ammonia,. maybe utilized for'otherpur I r Assuming for instance that .the gas icomingffrom theovens contains 1 1,1"grams hy-:

drogen sulfide and SA-grams' ammoniaper cubic metre (this being about thepercentage ofhydrogen sulfide and ammonia'jin the coke oven gases produced in the Ruhr district) thenthe main gas current contains about 32,2

per cent .hydrogen sulfide in; excess ofthe double equivalent of'aminoni a. Inowbranch eofi 2l53 per cent of the gases and return the ammonia contained therein into-themaingga-s monia and 8,2 grams hydrogen sulfidein current which thenlcontains gflgrams'ame 5 0,7 57 cubic metres; In this imannerabput'i 5 per centfof the hydrogenlsulfid a d all T ammoniacontainedin the gas are recovered The branch gas" current .freedfroin. its am with milk oflime and distilling the ammonia thusliberated in a steam current, the ammonia be ng then returned llliEO the main gascur-j rent. Thebranch current'is subjected toa washing'foperation inv order to recover the ammonia still contained therein which .i is P passed inst-0 Still nd thusreturned; in t o theimain: gas, current. V v

"I have found that my invention is ap pli a cable with particular-advantage .to'gas pro ducers,irom'which-thegas shall be supplied; to the consumers free from hydrogen sulfide,

while part of the gas is required for heating.

purposes in the producer plant itself or for other purposes which the presence ofhydrogen sulfide is innocuous Thenew method is particularlyvaluable in the case where all; the ammonia is washed out from the gas and the hydrogen sulfide islutiliz edifor the formation of ammoniumsulfateQ If in; this ca'sethe branch current containing the rest of hydrogen' sulfide is utilizedforheating the ice gas producers or ovens, about 50 per cent of the gas produced being as a rule required for this purpose, further 25,7 per cent of purl fied gas must be supplied to the branch current by all means, so that the percentage of hydrogen sulfide in the gas utilized for heating the furnaces or ovens is reduced to about 50 per cent. In this casein which for instance only 50 per cent of the total gas available shall be freed from hydrogen sulfide, the remaining surplus of ammonia may also be utilized for partly freeing the rest of the gas from hydrogen sulfide in accordancewith the surplus of ammonia.

In case that it should prove necessaryfor instance where the ovens are heated with gas produced elsewhere so that all the gas pro.- duced in the ovens can be subjected to treatment-to free all the as from hydrogen sulfide in the-simple conversion plants available for this purpose, I can do so in accordance with my invention by freeing the branch current from the hydrogen sulfide contained therein by well known means, for instance by dry purification with bog iron ore or the like, the hydrogen sulfide thus recovered being thereafter returned into the main gas current, preferablybefore this latter enters the hydrogen sulfide washers, In order to be able to effect the branching off of'part of the gas in accordance with the conditions prevailing in each individual case, it ismerely necessary to choose the quantity of gas to be branched off in proportion to the averageratio of hy-' drogen sulfide to ammonia in the gas produced from the coal under treatment. Any variations in this proportion may be provided for by causing the washing liquor used in the hydrogen sulfide extracting operation to contain a small quantity of ammonia by adding the required quantity of ammonia liquor if necessary. 7

In the drawing aflixed to this specification and forming part thereof an apparatus for carrying out this invention is illustrated diagrammatically by way of example.

As shown in the drawing, the crude gas flows through the pipe 10 into the cooler 11. The condensate separating out in the cooler andcontaining ammonia flows through pipe 12 into the reservoir 13, the cooled gas flows through pipe it into the washer 15 in which the surplus shall be removed. However before entering, the washer part of the gas is branched off by means of automatically ac tive devices of a well known kind and flows through pipe 16 into the ammonia washer 17. The ammonia liquor escaping from this washer flows through pipe 19 into the reservoir 13, while the gas freed from hydrogen sulfide escapes through pipe 18. The'condensate from the reservoir 13 flows in a quantity regulated by a valve 22 into the still 20 and the ammonia vapors developed in this still pass through pipe 21 back into the main The ammonium thiosulfate resulting in either one of these reactions is separated from the elementary sulfur or the insoluble sulfurcompounds and treated with S0 according to the equation Preferably the treatment with S0 is carried through in such manner that only part of the thiosulfate is converted into polythionate. On heating the liquor containing thiosulfate and polythionate, ammonium sulfate and sulfur are formed according to the equation 7 L) 2SiO6+2 NH, 23203; I 3(NH4) 2 044-53;

After removal of the sulfur the ammonium sulfate solution is concentrated by evaporation, pure crystallized ammonium sulfate be ing thus obtained.

This process is applicable with advantage in all the cases, where a surplus of hydrogen sulfide is present in the gas produced in the retorts or ovens. It has proved to be particularly useful whenever it is desired to recover ammonium sulfate by means of the hydrogen sulfide contained in the gas and the ammonia recovered in an ammonia recovery plant connected with the gas producers. For in such a case the ammonia washers forming part of the ammonia plant can be utilized for this process.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

I claim V 1. The method of removing from industrial gases containing hydrogen sulfide and ammonia in the proportion of more than one mol. H S to two mols. NH all the ammonia with part of the hydrogen sulfide to obtain. a gas free of H 5 and NH}, and a gas free of NH comprising dividing the quantity of gas to be treated into two parts, recovering ammonia from one of these parts, adding such ammonia the other part to establish therein theproportion of lI-LS to QNH and causing combination of H S and NH in this part.

2. The method of removing from indus trial gases containing hydrogen sulfide and ammonia in the'proportion of more thanone mol. H S to two mols. NH all the ammonia with part of the hydrogen sulfide to obtain a lish in said other part the proportion of IH S to 2NH recovering the ammonia from said one part, adding the ammonia thus recovered to said other part and causing combination of H S and NH in this part.

3. The method of removing from industrial gases containinghydrogen sulfide and ammonia in the proportion of more than one mol. H S to two molslNH all'the ammonia with part of the hydrogen sulfide to obtain a gas free'o'f H 8 and NH; and'a gas free of NH comprisingcooling the gas to separate 7 out the tar contained therein dividin'g the off gas separately from the hydrogen sulfide:

contained therein and returning the gas I which has thus been freed from ammonia and hydrogen sulfide; into the mainbody of gas and treating said main body of gas with a slightly ammoniacal washing liquor to free same from sulfur. V 1

In testimony whereof I FRANZ (BUNNEMANNQ quantity of gas tobe treatedintojtwo parts,

one part containing the quantity of NH required to fill up the ammonia in the other part so as to establish'in said other part the proportion of IH S to '2NH recovering the l ammonia from said onepart, adding the am-' i 1 monia thus recovered to said other part and causing combination of-H S and NH in this v part.

4. The method of removing from indus trial gases containing hydrogen sulfide and ammonia in the proportion of more than one mol. H s to two mols. NH all the ammonia with part of the hydrogensulfide to obtain: a gas free of H S and NH and a gas free of NH comprising branching off from the gas that quantitywhich contains the surplus of hydrogen sulfide beyond the ratio of 2 parts 7 ammonia to 1 part hydrogen sulfide,recover ing the ammonia contained in the branched off gas portion, returningsaid ammonia into the main body of gas, freeing the branched ofii' gas separately from the hydrogen sulfide contained therein and returning the gas which'has thus been freed from ammoniafand hydrogen sulfide, into the main body of gas.

5. The method of removing from industrial gases containinghydrogen sulfide and ammonia in the proportion of more than one mol. H S to two mols. NH allthe ammonia with part of the hydrogensulfide toobtain a gas free of H 8 and NH; an'da gas free of NH comprising branching off from the gas that quantity'which contains the surplus of the main body of gas, freeing the branched aflix signature.

hydrogen sulfide beyond the ratio of 2 parts I ammonia to 1 part'hydrogen sulfide, recover- 1 ing thesammonia contained in thebranched off gas portion, returning said ammonia into 

